Prior to a flight, a pilot has numerous duties to perform. One of these pre-flight duties may include a review of both present and past discrepancies reported for the aircraft. Present discrepancies may be those reported but not yet repaired, and past discrepancies may be those reported and repaired. Most of these discrepancies are unplanned or unscheduled, and many of them are originated by pilots who discover the discrepancy. Because these type of discrepancies arise randomly, these may be considered unscheduled maintenance actions.
Scheduled maintenance actions may be those that do not arise randomly. Generally, aircraft maintenance actions may be scheduled in intervals measured by a number of hours or cycles, or by the calendar. Personnel other than pilots may be tasked with the monitoring or tracking of the number of hours, cycles, and/or days being accumulated by the aircraft. When the aircraft has arrived at an hour, cycle, and/or day applicable for a scheduled maintenance action, notice may be provided to aircraft maintenance personnel so that the action may be performed.
While a mechanic may receive notice, a pilot may not be made aware of an action(s) that is due now or due soon. If the pilot plans for a lengthy flight or a flight in which numerous take-offs and landings (i.e., cycles) are anticipated, a scheduled maintenance action may become past due inadvertently. If a scheduled maintenance action exceeds a limit of its interval, the aircraft may not be considered airworthy; even if it is safely flown, the pilot may be subjected to penalties levied by an aviation governing authority such as, in the United States, the Federal Aviation Authority (FAA).